Alight emitting diode (LED) is a device able to emit light when electrical energy is applied thereto. An LED converts energy generated due to electron-hole recombination occurring at a p-n junction between p-type and n-type semiconductors into light to be emitted thereby. Such an LED is widely used as a light source in an illuminating apparatus, a display device or the like, and the development thereof is therefore being accelerated.
In particular, with the increasingly widespread use and commercialization of cell phone keypads, side viewers, camera flashes and the like using a GaN-based LED whose development and use are currently being accelerated, the development of a general illuminating apparatus using an LED is also being undertaken. LEDs are being applied to large-sized, high output and high efficiency products such as backlight units for large TVs, vehicle headlights, general illuminating apparatuses and applications thereof, and thus, the characteristics of LEDs used therefor need to be improved.